In lifted 4WD trucks using much larger tires, owners say they often see a decrease in fuel economy. This leads me to wonder, how does tire size (specifically, outside diameter) affect efficiency?
In my way of thinking, a wheel/tire having a larger OD than stock would result in fewer engine RPMs at a given speed (say 60mph). Conversely, using a wheel/tire having a smaller OD than stock would increase engine RPMs at the same speed, thereby leading to more fuel consumption.
Am I on track?